Hypotensive effect of a phosphorus-containing novel angiotensin converting enzyme inhibitor, (S)-1-[6-amino-2[[hydroxy(4-phenylbutyl)phosphinyl] oxy]-1-oxohexyl]-L-proline (SQ 29,852) in conscious hypertensive dogs.

The hypotensive efficacy of (S)-1-[6-amino-2[[hydroxy(4-phenylbutyl) phosphinyl]oxy]-1-oxohexyl]-L-proline (SQ 29,852), a phosphorus-containing novel angiotensin converting enzyme inhibitor (ACEI) was examined in conscious two-kidney, one-clip Goldblatt hypertensive dogs. The acute hypotensive effect of SQ 29 852 was compared with that of captopril or enalapril at 3 mg/kg, p.o., for each, and the potencies were ranked as follows, enalapril greater than SQ 29,852 greater than captopril. On the other hand, the hypotension caused by repetitive dosing with SQ 29,852 (3 mg/kg, p.o./d for 7 d followed by another 7-d treatment with 10 mg/kg, p.o./d) was somewhat more marked than that by enalapril at the same dosage. Blood urea nitrogen (BUN) increased in all the animals given enalapril, while that in all of the SQ 29,852-treated animals did not increase. These results indicate that SQ 29,852 is a potent, and long-lasting ACEI with a possible low incidence of side effects.